There is a wide commercial market available for the use of high performance electronic real time clocks. One significant feature requirement of high performance electronic real time clocks is the use of a crystal to generate the time base for the oscillator circuitry. For example, a conventional prepackaged crystal oscillator includes a quartz crystal to provide the frequency reference, and an oscillator amplifier to excite the crystal to resonance, while other crystal oscillator circuit packages utilize an external quartz crystal. However, as the consumer need for more powerful, smaller and less expensive electronic systems continues to be a driving force behind many new products and systems that don't need quite the accuracy of a crystal oscillator but do need a relatively precise oscillator, the cost and size of conventional crystal oscillator real time clocks makes them prohibitive.
One solution to the conventional crystal oscillator has been through the use of the RC oscillator circuit. Although this has proven to be a somewhat acceptable solution for systems which require low performance oscillator circuits, it has fallen short for systems requiring the high performance such as in computer systems. This is primarily because RC oscillator circuits are not very stable during operation. The reason RC oscillator circuits are not as stable as crystal oscillator circuits is due to the lack of a stable oscillator element for use by the conventional RC oscillator circuits to phase-lock to or to count down from. As with crystal oscillators, RC oscillator circuits also take up too much pc-board area.
Accordingly, based upon the foregoing, it should be understood and appreciated that there is a need for a low power, monolithic crystalless integrated circuit oscillator that provides an output signal with comparable frequency stability with that of conventional crystal oscillators.